Cutter clamp



E. R. KAST CUTTER CLAMP Sept. 24, 1929.

Filed July 6,

1926 2 Sheets-Sheet l ,T .m r

PAPA- P/LF NVENTOR BYM. cwu

'T ATTORNEYS iii-*- Sept. 24, -1929. l E, R, KAST 1,729,582

CUTTER CLAMP Filed July 6, 1926 2 Sheets-Sheet 2 Ime/non if ad? PatentedSept. 24, 1929 UNITED STATES PATENT OFFICE EDWARD R. KAST, OF PEARLRIVER, NEW YORK, ASSIGNOR TO DEXTER FOLDER COM- PANY, OF NEW YORK, N.Y., .A CORPORATON OF NEW YORK CUTTER CLAMP Application filed July 6,1926.

' sired size.

It has heretofore been proposed, when cutting a pile of paper supportedon a table or the like, to clamp the paper with a straight clamp, 'theclamping surface of which is parallel with the table. Clamps such asthese, however, have certain defects and disadvantages, in that there isa tendency for the sheets of paper to slide out horizontally between theclamp and the table when engaged by the knife. This is particularly truewith certain grades of paper having hard surfaces, and in the event thepile of paper consists of printing or design work, it frequently happensthatthe sheets are severed across the printing or design work, producingwhat is techically known as bleeding the printed work and therebyruining the sheets with the resulting loss in material and labor to theprinter.

The objects of this invention are to provide paper clamping means whichavoid the difficulties and disadvantages above referred to; which may bereadily embodied in existing paper cutting machines without materialalteration in the construction thereof; and by the use of which thenormal massive construction of the clampino elements may be lightened.

This invention will be better understood by reference to theaccompanying drawing which illustrates several embodiments of theinventive idea and wherein Fig. 1 is a detail perspective view of apaper cutting machine equipped with a clamp embodying the presentinvention, parts of the machine being broken away for purposes ofclearer illustration;

Fig. 2 is a vertical sectional view on the line 2-2 of Fig. 1;

Fig. 3 is an end view of the clamp, showing diagrammatically thestraight cut obtained thereby and the inclined cut obtained by existingequipment;

Fig. 4 is a vertical sectional view illustrat- Serial No. 120,790.

ing diagrammatically the effect produced by a straight bottom clamp onthe pile of paper, prior to engagement of the knife therewith;

Fig. 5 is a view similar to Fig. 4f, showing the effect produced on thepile of paper by engagement of a straight bottom clamp and the knife;

Fig. 6 is a vertical sectional view illustrating diagrammatically theeffect produced on the pile of paper by engagement of the clamp of thepresent invention therewith;

'Fig Z is a vertical sectional view showing another embodiment of theinvention; and

Fig. 8 is a vertical sectional view showing another embodiment of theinvention.

Referring to the drawings, wherein like reference numerals designatelike parts throughout the several views, 5 indicates a portion of themain framework of one type of machine on which the invention may be usedand on which the cross head 6, carrying the cutter blade 7, is mountedto reciprocate vertically and transversely of the machine in the usualmanner (Fig. 1). The knife operating` shaft, indicated at 8, is suitablyjournaled on the machine framework and provided on the projecting endthereof with cranks, one of which is indicated at 9. The cranks areconnected, by means of links 10, 10 with the opposite end of the crosshead 6 so that when the knife operating shaft 8 is rotated the links 10,10 will cause the cross head and cutter blade to reciprocate verticallyand transversely of the machine. The shaft 8 is driven by the large gear11, rigidly secured to one end of the shaft, and meshing with a clutchcontrolled driving pinion 12 which is mounted on the main power shaft ofthe machine (not shown). The table or support 13 for the pile of paper14 is mounted on the machine framework in the usual manner and carries aback gauge 15 controlled from the front of the machine by a band orcable 16 which passes around pulleys mounted on the underside of thecable and one of which is indicated at17. The paper holding clamping baror plate, indicated at 18, is provided at its end with downwardlyextending guide bars 19, 19 whereby the clamping bar or plate isslidably mounted on the machine framesol work for vertical reciprocatingmotion. The clamping bar or plate 18 carries the usual weight bar 2Owhich is reciprocated with the clamp 18 as the latter is raised andlowered to engage or disengage the pile of paper 14 on the table 13. Thelower ends of the guide bars 19, 19 have secured thereto in any desiredmanner the ends of chains 21, 21 which pass over pulleys or sheaves 22,22 journaled in any suitable manner on the machine framework. Theopposite ends of the chains 21, 21 are connected with rods 23, 23anchored as at 24, 24 to the ends of a. counterweight 25 for balancingthe weight of the clamp 18 and parts carried thereby. The ends of thevcounterweight 25 are pivotally connected as at 26, 26 with arms 27, 27fixed on shaft 28 journaled in suitable bearings 29, 29 on the machineframework The shaft 28 has fixed thereon a bell crank, one arm 30 ofwhich carries a foot piece 31, the arm 32 of said bell crank extending`within a slot 33 formed in the underside of the counterweight 25.

The guides 19, 19 are provided at the bottom thereof with rack blocks34, 34 which mesh with segmental gears 35, 35 fixed on a driven shaft36, each end of which is journaled in a bracket 37 secured to themachine framework. The shaft 36 carries at one end a friction wheel 38engaged by a slip clutch 39 connected with an arm 40 loosely mounted onthe driven shaft 36. The arm 40 is connected with one end of a pitman41, the opposite end of which is connected with a crank 42 fixed on oneend of a shaft 43 journaled in described, actuates the rack blocks 34,34 on the guides 19, 19, the arm 32 thereafter ele- Vati-ng theco-unterweight 25 so that the paper clamping bar or plate 18 descendsand engages the pile of paper 14 as shown in Fig. 2. When pressure isremoved from the foot plate 31, the parts illustrated in full lines inFig. 1 return to the position there shown. The pinion 12 when clutchedto the power shaft by the usual control means, causes the gearingdescribed above to move the bar 18 into clamping engagement with thepile 14, the clutch 39 and friction wheel 38 serving to control theapplication of the necessary pressure on the pile 14 by the bar or clamp18. At the same time, the knife operating shaft 8 causes the 'knife 7 tomove downwardlyand transversely of the machine so as to cut the pile ofpaper 14 clamped on the table 13. These operations take place duringonehalf of the revolution of the knife operating shaft 8, the succeedinghalf revolution of said shaft causing the paper clamping bar or plate18, the cross head 6, and the knife 7, to be lifted to the positionshown in Fig. 1.

Referring now to Figs. 4 and 5, it will be noted that when a straightbottom clamp such as indicated at A, firstengages the pile of paper, itcompresses the pile to a certain extent, thus bending portions of thesheets in the slanting positions indicated by the lines R-R and S-S withresulting forces which counteract each other so that no endwise movementof the sheets between the clamp and the table occurs. The motion of theknife B, however, is so timed that it engages the pile immediately afterthe clamp, thus building up additional pressure on the pile and furthercompressing the same before the knife cuts through the pile. As shown inig. 5, this additional pressure bends por.- tions of the pile of sheetsin positions shown by the lines T-T and U-U. The normal reaction fromthe combined pressure of the knife and clamp is indicated at N and thepressure on the table is indicated at V, leaving an unbalanced force H.The paper being confined by the clamp and table, this unbalanced force Htends to slide the sheets horizontally so that when the sheets areunclamped, it is generally found that they have not been cut accurately.This difficulty is of long standing and has characterized all thestandard types of cutters with which I am acquainted. Efforts to avoidsuch angular cuts have usually been directed along the line 1of applyingmore pressure `onthe .clamp and change in the shape of the cuttingknife, but this has proved unavailing. However great the pressureapplied, the angular cut will still be made and this has evidently beencaused, as above indicated, by the additional pressure applied to thepile of sheets by the cutting knife.

I have discovered that a straight cut normal to the paper support, suchas indicated by the full arrow in 3, can kbe produced through the pileof paper 14 by progressively increasing the pressure applied by theclamp from its front edge to its rear edge. This may be accomplished byproviding the clamping bar or plate 18 with a paper engaging surface 44gradually inclined or curved upf wardly from the rear edge of the clamto the front edge of the same. When a clamp thus constructed is loweredintov engagement with a pile of paper, the pressure on the pile exertedby the clamp progressively decreases from the rear edge of said cla-mpto the front edge thereof or progressively increases from the knife andthe front edge of the clamp to the rear edge of the latter. This isdemonstrated by reference to Fig. 2 wherein it will be noted that thelportion of the pile 14 disposed under the surface 44 progressivelyincreases in height from the rear edge of the lll clamp towards itsfront edge and toward the knife.

With a clamp such as last described, the pile 14 is so held that theadditional pressure of the knife 7 when it engages the pile will notdisplace the sheets as heretofore, and a shear cut absolutely normal tothe clamp is secured. The progressively increasing pressure of thepresent clamp on the pile rearwardly of the knife, or as otherwiseexpressed, the progressively decreasing pressure of said clamp on thepile from the rear edge of the clamp toward the knife, counteracts thedisplacing tendency of the knife, the inclined surface 44 of the clampengaging the pile, acting as a wedge to prevent horizontal displacementof the sheets between the clamp and the table. This is demonstrateddiagrammatically with the embodiment of the invention shown in Fig. 6,where the normal resistance to the clamp face is indicated at N and thevertical reaction on the table is indicated at V. In this instance,however, the horizontal component I-I tends to push the paper in adirection opposite to the force H of Fig. 2, so that a wedging effect isproduced by the inclined bottom of the clamp which, as above stated,counteracts the tendency of the sheets to slip horizontally between theclamp and the table by the additional pressure of the knife on the ile.

p The embodiment of the invention shown in Fig. 7 is substantially thesame in construction and operation as that illustrated in Figs. 2, 8 and6, except that in the present instance the rear edge of the clamp 18 iscurved as at 18 so that a sharp edge that might mar the stock isavoided.

In the embodiment shown in Fig. 8, the effect produced by cuttingthrough the clamped paper is the same as results from the employment ofclamps such as illustrated in Figs. 2, 3, 6 and 7. In this instance,however, a straight bottom clamp A, such as illustrated in Figs. 4 and5, is employed, but the table or support has an inclined angularclamping and supporting surface 13 for the pile of paper, so that whenthe knife B engages and passes through the pile of paper, it will make astraight cut therethrough instead of the angular cut resulting when astraight bottom clamp and a pile supportparallel therewith are employed,the pressure on a pile of paper clamped between the surface 13 and thebottom of the clamp A, progressively decreasing from the rear edge tothe front edge of said clamp Ior progressively increasing from the knifeB and the front edge of the clamp to the rear edge of the latter.

With this construction of clamp plate it is' possible to largely reducethe massive construction of the pressure devices heretofore employed andto largely reduce the clamping pressure heretofore applied, while at thesame time securing results with respect to accuracy of cut that it hasheretofore been impossible to secure. The clamp plates or pile Supportsof all makes of cutters such as the Dexter, Sibold, Sheridan andChandler and Price can be readily changed to embody this invention, thuscorrecting simply and economically a difculty that has long troubled theart.

While the degree of bevel of the face of the clamp plate may be variedfor different sizes of cutters and clamp plates and different varietiesof stock to be cut, I have found that a bevel of 1/32 on aclamp plate 4wide gives entirely satisfactory results, though obviously I do notlimit myself to these particular proportions, as the invention consistsbroadly in inclining or b'eveling the clamp face to secure the desiredresults.

What is claimed is:

1. The combination with a knife and means for supporting a pile ofpaper, of a clamp for engaging the pile of paper while the same is beingcut and adapted to apply successively decreasing pressure on the pilefrom one side of the clamp to said knife.

2. The combination with a knife and means for supporting a pile ofpaper, of a clamp for holding the pile on said means while the paper isbeing cut, said clamp having a paper engaging surface inclined upwardlyto the knife so as to apply successively decreasing pressure on saidpile from the clamp to said knife.

3. The combination with a knife and a support for the paper to be cut,of a clamp for holding the paper on its support while being cut, saidclamp having a paper engaging surface gradually increasing in heightwith respect to the support, from the side of the clamp remote from saidknife.

4. The combination with a knife, of a clamp and a support between whichpaper is clamped to be cut by the knife, one of said lastnamed elementsbeing adapted to engage the paper so that the clamping pressure thereongradually decreases to the knife.

5. The method of clamping a pile of paper to be cut, which consists inapplying gradually decreasing pressure on the pile from a point at oneside of the line of cut to said line.

In testimony whereof I have signed this specification.

EDWARD R. KAST.

